ISINGLASS

mica, isinglass

(noun) any of various minerals consisting of hydrous silicates of aluminum or potassium etc. that crystallize in forms that allow perfect cleavage into very thin leaves; used as dielectrics because of their resistance to electricity

Source: WordNet® 3.1

Etymology

Noun

isinglass (usually uncountable, plural isinglasses)

A form of gelatine obtained from the air bladder of the sturgeon and certain other fish, used as an adhesive and as a clarifying agent for wine and beer.

A thin, transparent sheet of mica (probably from its similarity to true isinglass).

Source: Wiktionary

I"sin*glass, n. Etym: [Prob. corrupted fr. D. huizenblas (akin to G. hausenblase), lit., bladder of the huso, or large sturgeon; huizen sturgeon + blas bladder. Cf. Bladder, Blast a gust of wind.]

1. A semitransparent, whitish, and very pure from of gelatin, chiefly prepared from the sounds or air bladders of various species of sturgeons (as the Acipenser huso) found in the of Western Russia. It used for making jellies, as a clarifier, etc. Cheaper forms of gelatin are not unfrequently so called. Called also fish glue.

2. (Min.)

Definition: A popular name for mica, especially when in thin sheets.

Source: Webster’s Unabridged Dictionary 1913 Edition